Don't Submit one article more then 2 to 3 good article directories its not good if you are looking for long term benefits, always create unique content for new submission and promote your submissions to that will be more beneficial rather then submitting same content in different article directories.

On SEO perspective - uniqueness plays a great role when we talk about popularity and authority, not to mention the penalty from SE about duplicate contents. Better not to submit the same article to the same site or any other sites. I know some uses tools like spinners to make their contents unique, in one way or another it will surely give you the benefit to create many unique articles thus saving you time and money as well.

I understand that submitting to multiple directories won't increase my SEO effort. But in my specific niche, good information is highly valued and hard to come by. From the articles, I am looking to gain traffic and potential sales more than SEO. I just wanted to make sure that my website wasn't going to be punished in anyway for the submissions.

With the recent updates in Google algorithm it is recommended that you don't submit the same article to multiple article directories, you should try to submit an article only at one place on the web. You can spin your article using any article spinning tool and get different versions of your article and submit each version on each article directory but you have to make sure that your spun articles can be readable and not have grammatical mistakes. In order to achieve this you should know how to use a spinner properly and add synonyms manually.

No, don't submit same article in different article directories. If you really wanted to use same article to post in different sites then make use of rel=nofollow tag, so that you can overcome duplicate content issue.

Always go for unique articles. If you are not having enough data regarding your article then collect it first. Prepare your article for submission having useful data covering your complete article. Most of the article submitting sites are not allowed duplicate article. They strictly penalize for this action. So take your time & prepare for unique one.